基于极限超载的无衬砌浅埋土质隧道稳定性研究  

Theoretical research on whole stability of unlined shallow earth tunnels based on ultimate surcharge

作　　者：程小虎 庞振勇 曾东洋[2] 曾德光 

机构地区：[1]北京城建设计发展集团股份有限公司,北京100037 [2]中交第一公路勘察设计研究院有限公司,陕西西安710075

出　　处：《岩土力学》2016年第3期835-841,共7页Rock and Soil Mechanics

摘　　要：为了从理论上判别和度量无衬砌浅埋土质隧道的稳定性,考虑拱形隧道洞身范围斜向滑裂面作用,采用极限平衡法导出隧道发生整体失稳时的极限超载与稳定安全系数理论解,并通过既有典型加载试验进行验证。浅埋隧道极限超载理论解与典型加载试验结果较接近,在此基础上,将抗滑力与滑动力之比定义为整体稳定安全系数,并分析其影响因素。研究表明,稳定安全系数随黏聚力、内摩擦角的增大而增大,黏聚力对其影响显著,而内摩擦角对其影响不显著;稳定安全系数随隧道跨度、覆跨比、超载的增大而减小,但超载越大对稳定安全系数影响越小;随着高跨比的增大,若黏聚力较低则安全系数减小,若黏聚力较高则安全系数先增大后减小。通过典型的加载试验对整体稳定安全系数进行了校验,表明稳定安全系数计算值基本满足工程允许误差要求。To discriminate and measure the whole stability of unlined shallow earth tunnel in theory, considering the effect of oblique slip surface beside tunnel body, a theoretical solution of ultimate surcharge is deduced by adopting the limit equilibrium method during the occurrence of the tunnel overall instability, and then the solution is examined using the typical loading tests. It is found that the solution of ultimate surcharge formulation is close to the test results. On the basis, the ratio of sliding resistance to sliding force is defined as the whole stability safety factor, and its influencing aspects are analyzed. It is shown that the stability safety factor increases along with the increment of the cohesive force and the internal friction angle, and the effect of cohesive force on the safety factor is significant, but the effect of internal friction angle is less potent. The stability safety factor decreases with the increment of the span, the depth-span ratio, and the surcharge of earth tunnel, but the surcharge has less effect on the stability safety factor when it is larger. With the increment of the height-span ratio, the stability safety factor decreases as the cohesive force is low, but it increases firstly and then decreases as the cohesive force is high. Finally, the whole stability safety factor is verified by typical loading experiments, demonstrating that the calculation error is within the engineering allowance.

关 键 词：浅埋隧道 整体稳定性 极限超载 安全系数 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]